1. Technical Field of the Invention
This invention relates to fluid mixing valve and more particularly to a hot and cold water mixing valve.
2. Disclosure Information
Mixing valves are constructed with movable plates slidably mounted over a stationary plate. The movable plate is constructed for both translational and rotational movement with respect to the stationary plate. The movable plate most commonly has apertures therethrough which can be aligned or misaligned with respect of hot and cold ports through the stationary plate. Alternatively, the movable plate may have a notch at its periphery which can be aligned or misaligned with respect to arcuate openings in the stationary plate. A control mechanism includes a knob or operative lever that is operably connected to the movable plate.
The problem with all of these rotational and translationally movable plates is the narrow angle through which the aperture actively mixes the hot and cold water. Commonly the rotational angle of displacement is approximately forty (40) degrees from the position where only hot water flows to the position where only cold water flows. Because of the relatively limited degree of the mixing angle, a slight angular displacement of the control mechanism causes a relatively large temperature variation in the water. The large temperature variation is usually more severe near the midway point between the hot only and cold only position at what is commonly referred to as the comfort zone. Because of the large temperature variations corresponding to the slight angular displacement of the control mechanism, it is difficult to finely control temperatures near the comfort zone.
What is needed is a mixing valve that is constructed to allow mixing through an increased angular displacement of the moving plate. The angular displacement can be as large as approximately 180 degrees for controlling mixing water from two ports. What is also needed is a valve plate having a shape that cooperates with the stationary plate to slow down the rate of temperature change with respect to the angular displacement of the moving plate when it is within the comfort zone.